Body support

ABSTRACT

A BODY SUPPORT INCLUDING A PLURALITY OF PLIANT OUTWARDLY EXTENDING AIR CELLS WHICH ARE IN COMMUNICATION WITH ONE ANOTHER THROUGH A BASE. WHEN LOADED THE AIR CELLS SUPPORT THE LOAD WITH SUBSTANTIALLY THE SAME FORCE PER UNIT AREA IRRESPECTIVE OF THE AMOUNT THEY ARE DEFLECTED.

R. H. GRAEBE BODY SUPPORT sep; 2o, 1911 FiledA Dec 5'. 1568 2Sheets-Sheet 1 l//l/ lll/lill l f f. Lf mi m6, e maw r IP R. H. GRAEBEsept. zo, 1911 BODY SUPPORT 2 Sheets-Sheet 2 Filed Dec. 5, 1968 mm f/'/|V/ Alf/ K FIG.6

United States Patent O 3,605,145 BODY SUPPORT Robert H. Graebe, 4 SignalHill Blvd., East St. Louis, Ill. 62203 Filed Dec. 5, 1968, Ser. No.781,472 Int. Cl. A47c 27/08 U.S. Cl. -348 11 Claims ABSTRACT OF THEDISCLOSURE A body support including a plurality of pliant outwardlyextending air cells which are in communication with one another througha base. When loaded the air cells support the load with substantiallythe same force per unit area irrespective of the amount they aredeflected.

This invention relates generally to cushioning devices and in particularto body supports for supporting a body in such a manner that thesupporting force is distributed substantially uniformly over the portionof the body which is in contact with the support.

Conventional body supports such as mattresses or seat cushions generallyemploy a multiplicity of interdependent coil springs arranged on a basein a uniform pattern with a foamed or some other type of paddingextending across their upper ends. Springs, however, resist the loadplaced upon them with a force proportional to the amount they aredeflected. Consequently, those springs within a mattress which aredeflected most bear against the body with the greatest force In the caseof invalids, hospital patients, and others who are confined to beds orwheelchairs for extended periods of time, this characteristic ofconventional spring mattresses or cushions can have deleterious effects,particularly on those areas of the individuals skin which bear most ofthe body weight. More specifically, painful decubitus ulcers or bedsores often develop at these locations by reason of the fact thatcapillary blood vflow at these areas is greatly restricted, and this isparticularly true where the supporting contact is at a bony prominence.

Mattresses constructed from foams and other paddings as well asconventional air mattresses react similarly when subjected to loading,although the relationship between the deflection and load is notnecessarily proportional. Nevertheless, certain limited areas of thesematresses bear most of the body weight, as is the case with innerspringmattresses and cushions, and therefore such mattresses inducediscomforting bed sores.

One of the principal objects of the present invention is to provide abody support which produces substantially uniform loading across thecontact area of the body supported by it. Another object is to provide abody support which reduces the possibility of decubitus ulcer formationon the bodies of confined individuals to an absolute minimum. A furtherobject is to provide a mattress or other body support which affordsadequate ventilation of the skin through the body support itself. Anadditional object is to provide a body support which is of a simple, yetrugged, construction and is economical to manufacture. A still furtherobject is to provide a body support which is comfortable for extendedperiods of time. Still another object is to provide a cushioning device3,605,145 Patented Sept. 20, 1971 for absorbing relatively severeimpacts. These and other objects and advantages will be apparenthereinafter.

The invention is embodied in a plurality of elongated air cells arrangedin side-by-side relation and in close proximity to one another so thatthe combined upper surfaces of the elements form a substantiallycontinuous supporting surface. Each air cell is adapted to resist aforce applied against it with a reactive force substantially equal perlunit area to that exerted by other air cells regardless of whether ornot the particular air cell is deflected the same amount as the otherair cells.

The invention also consists in the parts and in the arrangement andcombinations of parts hereinafter described and claimed. In theaccompanying drawings which form part of the specification and whereinlike numerals and letters refer to like parts wherever they occur:

FIG. l is a perspective view of a body support constructed in accordancewith and embodying the present invention;

FIG. 2 is a fragmentary sectional view taken along line 2F2 of FIG. 1;

FIG. 3 is a fragmentary plan view of the body support;

FIG. 4 is an elevational view of the body support supporting a contouredload;

FIG. 5 is a perspective view of a modified body support;

FIG. 6 is a fragmentary sectional view taken along line 6 6 of FIG. 5;

FIG. 7 is a fragmentary sectional view of still another modified bodysupport; and

FIG. 8 is a fragmentary plan view of the body support illustrated inFIG. 7.

Referring now to the drawings in detail, the numeral 2 of FIG. 1designates a body support including a base 4 and a pliant section 6 onwhich the invalid, hospital patient, or other individual using the bodysupport 2 is carried. The base 4, which can be either flexible or rigid,

is, in effect, a manifold and includes an upper wall 8 and a lower Wall10 which are marginally connected by integrally formed side walls 12 andend walls 14. Intermediate the side and end walls 12, 14, the upper andlower walls 8, 10, are interconnected by a plurality of restraining ribs16 having apertures 18 which provide communication between the chambers19 formed within the base 4 by the ribs 16. One of the end walls 14 isprovided with an inflation valve 20 which can be similar to aconventional tire valve. The upper wall 8 is provided with a pluralityof orifices 22 arranged in longitudinally and transversely extendingrows with the orifices 22 in adjacent longitudinal rows being staggered-with respect to one another. Should the upper wall 8 be pliable, it isdesirable to make it non-elastic, and this can be achieved by embeddinga flexible but non-elastic material such as cloth in an elastomeric wallforming substance.

The pliant section 6 includes a plurality of closely spaced parallel aircells 30 having substantially cylindrical side walls 32 which integrallymerge at the upper ends into circular top walls 34. Along their lowermargins the side walls 32 merge into a common connecting web 36 which,in turn, is vulcanized or adhesively secured to the upper surface of theupper wall I8 in surrounding relation to the orifices 22. In thisconnection, it should be noted that the web 36 maintains the air cells30 in longitudinally and transversely extending rows `with the air cellsof adjacent longitudinal rows being staggered to provide a greaternumber of air cells for a given surface area as best seen in FIG. 3.Moreover, the pattern established by the axial centerlines of air cells30 is identical to that formed by the orifices 22 in upper wall 8. Sincethe web 36 is secured to the upper wall 8 in surrounding relation to theorifices 22, each orifice 22 opens upwardly into a different air cell30. The circular top walls 34 of the air cells 30 are closely spaced andare disposed such that they form a generally continuous upper supportingsurface on the pliant section 6.

Preferably the pliant section 6 is formed as an integral unit from asuitable substance such as latex rubber. The thickness of the substanceat the cell walls 32 should not be so great as to impart large restoringforces to the cells when they are deflected. On the contrary, little ifany restoring force should be imparted by reason of the naturalresiliency of the material from which the walls 32 are formed. Ideally,the cells 30 of the pliant section 6 should not be free-standing, yetshould be strong enough to resist ballooning when subjected to elevatedinternal pressures of the magnitudes encountered in the application forwhich they are designed. In the case of the latex rubber, it should beapproximately 14 to 16 mils thick at the walls 32 and 34 of the cells30.

One method of forming the pliant section 6 is to dip a patternconsisting of a flat base having a multiplicity of cylindrical elementsprojecting from it into a vat of liquid latex rubber. Ten to twenty dipsare required to produce the desired wall thickness. After the latex hasset, the pattern is removed leaving the pliant section 6 which issubsequently secured to the base 4 such that the orifices 22 open intoindividual air cells 30.

In use, the body support 2 is first inflated by directing air from asuitable source into the base 4 and air cells 30 through the inflationvalve 20. If the base 4 is formed from a flexible substance, therestraining ribs 16 prevent it from ballooning outwardly into anelliptical shape. When the desired pressure is attained, the base 4 isplaced on a supporting surface (not shown). If the body support 2 is toserve as a seat cushion, this supporting surface could be the seat orbackrest of a wheelchair or other type of chair. -On the other hand, ifthe body support 2 is a mattress, then it is desirable to lay it on aplywood or other type of rigid supporting member which has previouslybeen laid across the bed rails of a bed. Be that as it may, the base 4may be placed directly upon a mattress of a bed and that mattress willprovide sufllcient subjacent support. The base 4 can also be placed on aconcave surface, in which case the axes of the air cells 30` would tendto out- Wardly converge. Accordingly, the cells 30 would be less likelyto spread when subjected to loading.

The user, of course, rests on the generally continuous surface formed bythe circular top walls 34, and in so doing he will deflect or crush theair cells 30 downwardly in conformity to the contour of his body asillustrated in FIG. 4. This deflection increases the pressure within theair cells 30 until an equilibrium condition is reached, at which pointthe user will be completely supported by the air cells 30. Since eachair cell 30 is in communication with every other air cell 30 through theorifices 22, the chambers 19 and the apertures 18 ywithin the base 4,the pressure within each air cell 30 as well as the air pressure at anylocation within the base 4 will be the same. Inasmuch as the forceapplied by any one air cell 30` to the users body for all practicalpurposes equals the pressure within the air cell 30 multiplied by thearea of its top wall 34, the force exerted by each air cell will beidentical irrespective of the amount of deflection, assuming, of course,that all of the top walls 34 possess equal areas. Even if the areas ofthe top walls 34 are different, the force per unit area or pressureexerted by @h air Cell 30 on the supported body will be the same andthat is the significant factor. Consequently, the portions of the usersbody which protrude furthest into the resilient section 6 will not bearan inordinate amount of his weight, while other portions escape withoutbearing hardly any of the weight at all. On the contrary, the supportingforce exerted by the resilient section 6 on the users body will bedistributed evenly over that portion of his body in contact with the aircells 30, and by reason of this fact, the forces on any one point arekept below the level (30 mm. of Hg) which normally impedes capillaryblood flow to such an extent that bed sores develop. Moreover, aircirculates freely through the voids between the air cells 30, and thisnot only permits dissipation of perspiration and the drainage of bodywastes, but also has a general therapeutic effect on the users skin.

When both the base 4 and the pliant section 6 are constructed from aflexible material, the body support 2 can be used on the articulatedframes of conventional hospital beds, in which case the regular mattressis used to provide subjacent support for the body support 2.

Also, the body support 2 can consist of several different modules havingdifferent internal pressures when unloaded for providing a firmer orsofter support, whatever the case may be. For example, in a mattress itmay be desirable to provide a somewhat firmer support in the pelvic andscapular regions than at the skull and heels. In such an instance adifferent module would be used for each region, and the air cells 30`and air chamber 19 of each module would be in communication with eachother, but not with the air cells 30 and the air chambers 19 of adjacentmodules. To a limited extent, the same effect can be achieved byaltering the spacing between adjacent air cells 30 or by varying thecross-sectional size of such air cells. In this manner the supportingforce supplied by the pliant section 6 is spread out over a greater orconfined to a more limited portion of the skin. Be that as it may, theforce per unit area exerted by the air cells 30 of any particular pliantsection 6 still remains the same.

Air cells 30 between 4 and 6 inches in height and approximately 5%; inchin diameter have been found suitable for seat cushions, while greaterheights up to 10 inches are desirable for mattresses. The cells 30should be close as practical, 1/8 to 1A inch between cells 30 beingacceptable.

Referring now to FIGS. 5 and 6, it is possible to provide a modifiedbody support 50 including a base 52, a pliant section 54, and aperipheral restraining wall 56. The base 52 is very similar to base 4and includes upper and lower walls 58, 60, the former of which isprovided with a plurality of longitudinally and transversely alignedorifices 62.

The resilient section 54 consists of a plurality of upstanding air cells64 of rectangular cross-sectional shape and arranged in longitudinal andtransverse rows with the side faces of adjacent air cells 64 beingnormally in facewise, yet detached, abutment. The air cells 64 are,moreover, molded or otherwise formed from an open celled low densityfoam having little if any inherent resiliency when not otherwisesupported. Urethane has been found suitable for this purpose. Each aircell 164 is provided with a downwardly opening compression chamber 66which extends upwardly within that air cell 64, terminating in closeproximity to its upwardly presented outer surace. The inwardly presentedsurface defining each compression chamber 66 is coated with a generallyimpermeable latex or vinyl plastic, as is the downwardly presentedsurface of each cell 64. As previously noted, the cells 64 are arrangedupon base 52 with their side faces detached but in abutment, and when sodisposed each orifice 62 opens upwardly into a compression chamber 66 soas to establish communication between the chambers 66 and the interiorof base 52. The cells y64 are, moreover, held securely to the base 52 bymeans of a suitable adhesive located at the interface formed at thejuncture of the upper wall 58 and the coated bottom faces of the aircells 64. Each air cell 64 is, furthermore, substantially `the same-height as neighboring cells 64 so that a more or less continuoussupporting surface is formed across the upper portion of the resilientsection 54.

The peripheral restraining Iwall 56 is formed preferably from aresilient foamed material of the open cell variety such as urethane sothat air may pass through it and is secured to the base 52 insurrounding relation to the air cells 64 forming the resilient section54, thereby lending lateral support to the cells 64.

After the body support 50 is inflated to the desired pressure, it issuitable for use in a manner similar to the body support 2, that is,with the user resting upon the rectangular upper surfaces of the aircells 64. Again, when this occurs the cells `64 will deform and depressdownwardly in conformity to the contours of the users body until anequilibrium condition is attained, at which point each cell 64 willpress upwardly against the users body with substantially the same forceas the neighboring cells y64, thereby distributing the supporting forceof the resilient member evenly across that portion of the users body incontact with it. Also, air circulates freely through the open cells ofthe open celled foamed material forming the air cells `64, as well asthrough the open cells of the peripheral wall 56, and this as previouslynoted has great therapeutic and comfort value.

Referring now to FIGS. 7 and 8, it is possible to provide still anothermodified body support 80 which is Very similar to the body support 2.The body support 80 includes a solid or flexible base 82 and pliantsection 84, the latter of which integrally includes a multiplicity ofair cells 86 arranged in longitudinally and transversely extending rows,with the cells in adjacent rows being staggered with respect to oneanother. Each cell 86 includes a circular top wall 88 and afrusto-conical side wall 90 providing an ever changing cross-sectionalarea dependent on deflection, which together define an air chambr 92. Attheir lower margins the side walls 90 merger into and are connected toone another through an integrally formed connecting web 94 which isadhesive or otherwise secured to the base 82. The air chambers 92 ofadjacent air cells V86 are connected through embossed channels 96 formedwithin the web 94. In effect, the web 94 is contoured away from the base82 to form the channels 96. Consequently, each air chamber 92 will bemaintained at the same pressure irrespective of the amount itscorresponding air cell 86 may be deflected. The pliant section 84 may beformed by dipping a pattern, in the manner previously described, orvacuum forming or similar techniques of production. The body support 80,having frusto-conical side walls 90, when used with a pliable base 82will accommodate severe concave shapes such as would be required infootball helmets.

By restricting the size of the orifice 22, the body support 2 can beadapted to absorb localized transient impacts of a severe magnitudewithout complete collapse of the air cells 30 at the point of impact.This is also true of the body supports 50 and '80. Restricted orificesor channels approximately the size lof a pin hole have been foundparticularly useful in adapting the body supports 2, 50 and 80 for useas shock absorbing package liners and in safety devices such as linersfor safety helmets. Or crash protection systems in either case, whenimpacts of a localized nature are sustained, the air within the aircells at the point of impact cannot escape all at once into the airychamber of the base or into adjacent unloaded air cells, andconsequently the air cells at the point of impact give relatively slowlyand separate the conformal static load from the dynamic loads, therebyabsorbing the shock and distributing it over a relatively large area.Cell heights from 1A to l inch have been found suitable for use withhelmet liners.

It should be noted that the air cells 30, 64, and 86 have 6 two degreesof freedom, that is to say they compress longitudinally aud may furtherbe shifted laterally. Accordingly, they deflect laterally as well aslongitudinally in the presence of body members and will not pinch orconstrain those members.

This invention is intended `to cover all changes and modifications ofthe example of the invention herein chosen for purposes of thedisclosure which do not constitute departures from the spirit and scopeof the invention.

What is claimed is:

1. A cushioning device comprising base means forming a manifold, and aplurality of closely spaced elongated air cells mounted on the basemeans and projecting outwardly therefrom, the air cells having internalcompression chambers and being pliable so as to have at least twodegrees of freedom for longitudinal and lateral displacements wherebyloads will deflect the air cells and reduce the volume of theirchambers, the chambers of the air cells being in communication with themanifold so that the pressure within all the air cells will equalizewhen all or some of the air cells are subjected to loads.

2. A cushioning device according to claim 1 wherein the base meanscomprises first and second walls, located in spaced relation to oneanother in the formation of a continuous air chamber therebetween,wherein the first wall is provided with a plurality of apertures openinginto the continuous air chamber, and wherein the flexible air cells aresecured to the first wall adjacent their innermost ends in surroundingrelation to the apertures, whereby the interior of each air cellcommunicates with the air chamber so that the air pressure within eachair cell is equal.

3. A cushioning device according to claim 1 wherein each air cellcomprises a body portion formed from an open cell cellular material,wherein the internal compression chambers open outwardly toward the basemeans, and wherein the inwardly presented surfaces defining thecompression chambers are sealed with a substantially irnpermeablesubstance so that air cannot escape from the compression chamber throughthe open cells of the body portions.

4. A body support according to claim 3 wherein the cells are ofpolygonal cross-sectional configuration, wherein the side faces ofadjacent cells are normally in facewise abutment, and wherein the outersurface of each cell forms a substantial continuation of the outersurface on adjoining cells, whereby a substantially continuoussupporting surface is formed by the combined outer surfaces of thecells.

5. A body support according to claim 4 and further characterized by aperipheral wall mounted on the base means and extending around theoutermost air cells, whereby to lend lateral support to the air cells.

6. A body support according to claim 1 wherein the air cells areconnected to one another through a web attached to the base, and whereinthe web is provided with air channels for establishing communicationbetween the air cells.

7. A body support according to claim 6 wherein `the air channels areformed by embossments in the webs, the embossment being located inspaced relation to the base.

8. A cushioning device according to claim 1 wherein the manifold has agenerally continuous wall extending across one side thereof, the wallhaving apertures providing communication with the interior of themanifold; and wherein the pliable air cells are attached at their innerends of the generally continuous wall and have their interiors incommunication with the interior of the manifold through the apertures.

9. A cushioning device according to claim 1 wherein the outer ends ofsubstantially all of the air cells are detached from one another so thatadjacent air cells can move laterally and inwardly and outwardlyrelative to one another.

10. A cushioning device according to claim 9 wherein adjacent air cellscan move laterally in any direction relative to each other.

11. A cushioning device according to claim 8 wherein `the apertures arerestricted orifices which are substantially smaller in area than thetransverse cross-sectional area of the cells so that the conformalstatic pressures are separated from impact forces whereby the cellsdeflate slowly when impacts are sustained and thereby absorb the shockof the impact and distribute it over a large area.

8 References Cited UNITED STATES PATENTS BOBBY R. GAY, Primary Examiner10 P. A. ASCHENBRENNER, Assistant Examiner U.S. Cl. X.R.

